The PhytoDOAS algorithm by Bracher et al. (2009), modified by and Sadeghi et al. (2011), enables the concurrent retrieval of global chl-a of phytoplankton groups (diatoms,
cyanobacteria, coccolithophores, dinoflagellates) from hyperspectral satellite data, such as measured by SCIAMACHY onboard ENVISAT. For applying the Differential Optical Absorption Spectroscopy (DOAS) fit from 430-530nm the following absorbers are considered in the analysis: atmosphere: O3, O4, NO2, H2Og, Glyoxal, Ring;
ocean: inelastic scattering, water, PFTs;
The non-differentisl absorption and scattering is approximated with low order polynomial. The global data set of the four phytoplankton groups is avaiable on a monthly resolution for July 2002 until today.